This invention relates to a method of measuring lung function in a subject and to apparatus for use in carrying out the measurement.
The measurement of lung function in humans and other animals has various applications. In patients with emphysema or other respiratory tract diseases, the monitoring of lung function may be useful both in treating the disease and carrying out research. It is also useful to monitor lung capacity and function in sportsmen and women. Various other applications for such measurements exist.
Two significant parameters in measuring lung function are airway resistance (R.sub.aw) and compliance of the lung and thorax (C.sub.lt). These parameters are analogous to electrical resistance and capacitance, and define a time constant .tau.=R.sub.aw .times.C.sub.lt. Previously, airway resistance has been measured by the use of a body plethysmograph, while compliance of the lung and thorax has been measured by the use of a swallowed balloon. This is clearly a cumbersome and awkward procedure.
It is an object of the invention to provide an alternative method of and apparatus for measuring lung function.